egcs-19980824 AIX 4.3 build problem with 64-bit libraries

[David Edelsohn <dje at watson dot ibm dot com>]

	There still seems to be a problem with the commandline arguments
to "ar" on AIX 4.3.  This relates to my notes about AR_FOR_TARGET earlier.
When building on AIX 4.3, "ar" needs to be invoked with the -X32_64
argument so that 64-bit archives can be constructed.
gcc/config/rs6000/x-aix43 adds this to gcc/Makefile for use when building
libgcc.a multilib.  This it also needs to be set for all of the libraries
under the build-tree top-level "libraries" directory (libiberty, libio,
libstdc++, and libf2c) that are configured and built after GCC itself is
bootstrapped, i.e. with the target tools.

	I am not sure where from where this information should be
inherited.  "libraries" does know about multilib from --print-multi-lib,
not from anywhere in gcc/Makefile.  It looks like the top-level Makefile
reconstructs XX_FOR_TARGET from first principles.  It is not clear to me
where AR should be set and whether AR or AR_FOR_TARGET is used when
building stuff that should be build using target tools.  Does this need to
be in the top-level "config" directory in a new mh-aix43 file?

Thanks, David